I was looking at your profile, you're fifteen right? At that age I would ask myself, "Why am I cosplaying?" Is it because I like getting into character and acting like my favorite anime charater?
Is it because my friends do it and it looks like fun so I am doing it as well.
Or, because my friend went to an anime convention and asked me to come along dressed in this embarrassing costume they lent me.
It may not be the cosplaying itself that is the problem but the circumstances that instigated your becoming a cosplayer in the first place. At the age where you are leaving Middle School and entering High School you start to want to evaluate your lifestyle. You want to not look like a little kid and to act more adult, at least what you perceive being more adult to be. Peer pressure and your own sense of viewing the world may have you questioning yourself about wearing cosplay, especially wearing it to school. Maybe your friends or even you like wearing nekko mimi (cat ears) to school, or anime styled hats, T-shirts or gothic lolita dresses. Maybe you get comments from classmates that make fun of your appearance and categorize it as being geeky or weird. Believe me when I say that Junior High and High School aged people can be some of the cruelest individuals on the planet.
If you are deciding that you don't want to cosplay anymore because of peer pressure at school, then I would ask you to really look at why you cosplay in the first place. If you have been doing it because you like to act out your characters. Because you enjoy getting with groups of other cosplayers and playing games and having fun. Because you like having pictures taken of you, and enjoy being in the spotlight. Then I suggest you continue doing cosplay. Maybe not at school, but at cons and events. You may also try getting into drama classes at school so you can have a reason to dress up, and act, and be in the spotlight, and make new friends that enjoy the same thing.
If on the other hand you have only been cosplaying because your friends asked you to, and you don't really enjoy it all that much, and people look at you weird and make you feel uncomfortable. Well, then maybe you should consider stopping. The choice is always going to be yours. Only you know how you feel about cosplay, and only you can decide if you want to continue it or not.
I am over three times as old as you are, and I cosplay. I do it because I enjoy going to KCon and I enjoy the attention I get when people recognize my character and yell clear across the lobby "OMG, It's Hohenheim!" I also sing, run Anime Friday at my home every week, and was in a college production of
The Sound of Music. I also did a bit of VA work for an on-line comic.
You never know where your interest in cosplay may take you. Think about it hard, and make your decision. I hope to see you at KCon again someday. If you see Hohenheim walking around say hi!